1. Field of the Invention
The present invention relates to a collagen-based matrix for use as a restorative material. Particularly, the present invention relates to a collagen-based matrix with a bilayer structure composed of a dense layer and a porous layer, which is useful as a tissue restorative material offering excellent adhesiveness and healing effects. Type 1 collagen, typically obtained from animals, is converted into atelocollagen by removing telopeptides therefrom. The atelocollagen is dispersed in distilled water and forms a porous layer and a dense layer which are crosslinked with each other in the presence of EDC [1-ethyl-3-(3-dimethyl aminopropyl)carbodiimide] to afford a bilayer structure which is not separated in aqueous conditions and is processed into a matrix in a grid form. Thus, the present invention is also concerned with a method for preparing the collagen-based matrix.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98
With the increase of a population of patients suffering from burns, bedsores, wounds, intractable ulcers, ulcerative dermal necrosis or epidermal necrosis, great advances have been made in the treatment of injured skin. Even three decades ago, patients with 60% or more of the body surface area burned usually died of septicemia. However, artificial skin has recently been developed to prevent water loss and bacterial infection, making a significant contribution to a reduction in mortality.
Artificial skin is largely divided into a wound dressing and a cultured skin. The former is typically applied to local or non-serious wounds to protect the skin before skin grafting is conducted thereat or until a cultured autograft is obtained, which takes usually 3 to 4 weeks. As for the cultured skin, it is used to minimize scarring when serious skin loss occurs or a wound is generated over a wide area of the skin. In this regard, sufficient dermal cells are obtained using cell culture technology and applied for permanent engraftment.
However, the cultured skin must be tested for safety from various pathogens including viruses (HIV 1&2, HTLV &, CMV lgM, Hepatitis B & C, and adenovirus) as well as that related to bacteria, fungi, endotoxins and mycoplasma. When obtained from a dead body, skin remains in an unknown health state, and it is impossible to perfectly sterilize it from the fatal viruses because the body tissue cannot be thermally treated to the desired extent. Further, it takes at least one week to culture and graft cells, which is too long to treat a first-aid patient therewith.
Over and above cultured skin, the wound dressing has advantages that it is used over a broad area of the skin, is easy to handle, and can be applied to first-aid patients. However, it is used only for temporary treatment, not for permanent engraftment. Wound dressings made of natural polymers, such as chitin, chitosan, collagen, etc. are low in mechanical strength, expensive and difficult to produce on a mass-scale. On the other hand, when prepared from synthetic polymers such as silicon or polyurethane, the wound dressings are poor in biocompatibility and in making contact with wounds.